The invention relates to a gathering and stapling (stitching) machine that includes a gathering chain for conveying printed products and having a variable chain pitch, with a stapling device for stapling the printed products that are conveyed on the gathering chain.
The Applicant's Swiss patent publication CH-A-662 987 discloses a saddle stitcher having a drive device of this type. In this saddle stitcher, the stapling machine can be converted to a different saddle-chain pitch in that the step-down ratio of an advancing gear of the drive device is correspondingly changed, and the stroke path of the stapling carriage is adapted to the other chain pitch through an adjustment of a ball-headed spindle. The step-down ratio is changed corresponding to the selected chain pitch through the exchange of advance wheels. A conversion of the gathering-chain pitch permits an increase in the machine output. If, for example, the book bindery faces the task of stapling a large quantity of small printed products, it is worthwhile to select a correspondingly-small pitch of the conveyor device and adapt the machine accordingly. It is therefore known to alter the pitch of the conveyor device corresponding to the size of the printed products while maintaining the device's speed. Altering the pitch of the aforementioned saddle stitcher is, however, very time-consuming, and therefore does not occur often for smaller jobs. Furthermore, the conversion work requires appropriately-trained personnel.